Unique

A unique is an item of which only one of appear in the MUD at any given time (hence, unique). Because of this, uniques are typically very powerful items to be treasured highly by their owners.

A semi-unique is an item that usually resets very slowly, or is often difficult to obtain. It is different than a unique in that there can be more than one in the MUD at a time, yet there are always a very small amount of them.